The invention relates to drilling machines, and more particularly, to drilling machines having a movable rod handling device.
Drilling machines typically include a frame, a tower, and a rotary head. The frame is supported for movement over the ground, and the tower is mounted on the frame. The tower defines a longitudinal axis and includes elongated members, or chords, that extend parallel to the longitudinal axis. The rotary head is movable along the tower and is engageable with a drill string for rotating the drill string. The drill string is assembled from multiple drill rods.
The rotary head includes rotary head guides that are connected to opposite sides of the rotary head and that engage the elongated members to allow the rotary head to move upward and downward along the elongated members. The rotary head connects with the drill string, rotates the drill string, and forces the drill string downward to penetrate the ground and create a drilled hole.
Drilling machines also include rod handling devices that are used to hold drill rods or constrain their movement. Some rod handling devices include rod supports and rod catchers. During rod changing operations, a rod support is positioned along the tower to hold the lower, free end of a newly added drill rod to secure the drill rod while it is being threaded into the lowered drill string. During drilling operations, a rod support is positioned along the tower to provide lateral support and vibration resistance to the drill string that is being rotated by the rotary head. A rod catcher is used to keep unattached drill rods from escaping the tower.
Existing rod handling devices are generally mounted to the side of the tower for pivotal movement. For example, FIG. 1 illustrates a prior art rod support 1 that includes an arm 2 pivotably coupled to a side panel 3 of the tower 4 for movement between an operative, closed position adjacent the drill string 5 and an inoperative, open position located a distance away from the drill string 5. In the operative, closed position, the rod support 1 lies within the travel path of the rotary head 6 such that the closed rod support 1 interferes with the movement of the rotary head 6. In the past, interlock control systems have been used to avoid collisions between the vertically-moving rotary head and the rod support in the operative position. This known swinging-arm design imparts increased strain to the side panel 3 of the tower 4 because of the unique loading caused by the operation of the swinging arm 2.